Configuring DAI
Context
Configuring DAI on an access device can prevent MITM attacks and theft on authorized users' information. After DAI is configured, the device compares the source IP address, source MAC address, and interface number in the received ARP packet with binding entries. If the ARP packet matches a binding entry, the device considers the ARP packet valid and allows the packet to pass through. If the ARP packet does not match a binding entry, the device considers the ARP packet invalid and discards the packet.
The device enabled with DHCP snooping generates DHCP snooping binding entries when DHCP users go online. If a user uses a static IP address, you need to manually configure a static binding entry for the user. For details about the DHCP snooping configuration, see DHCP Snooping Configuration. For details on how to configure a static binding entry, see Configuring a Binding Table.
When the protocol packet transparent transmission in a VLAN is enabled together with the DAI function, the protocol packet transparent transmission function does not take effect.
- CE12800E does not support this function after having the ED-E, EG-E, and EGA-E series cards installed.
Procedure
- Run system-view
The system view is displayed.
- Run vlan vlan-id
The VLAN view is displayed.
Or run bridge-domain bd-id
The BD view is displayed.
- Run arp anti-attack check user-bind enable
DAI is enabled.
By default, DAI is disabled.
- (Optional) Configure check items configured for ARP packets based on binding entries.
- Run the arp anti-attack check user-bind check-item { ip-address | mac-address | interface }* command in the VLAN view.
By default, the check items consist of IP address, MAC address, and interface number.
- Run the arp anti-attack check user-bind check-item { ip-address | mac-address | vxlan-tunnel }* command in the BD view.
By default, the check items consist of IP address, MAC address, and VXLAN tunnel information.
To allow some special ARP packets that match only one or two items in binding entries to pass through, configure the device to check ARP packets according to one or two specified items in binding entries.
Check items configured for ARP packet check based on binding entries do not take effect on hosts that are configured with static binding entries. These hosts check ARP packets based on all items in static binding entries.
- Run the arp anti-attack check user-bind check-item { ip-address | mac-address | interface }* command in the VLAN view.
- Run commit
The configuration is committed.